How to detect incoming call

To listen for change in calls you can use a broadcast with action: android.intent.action.PHONE_STATE:

Code (Text):

1. <receiver android:name=".CallReceiver">
2.             <intent-filter>
3.                 <action android:name="android.intent.action.PHONE_STATE" />
4.             </intent-filter>
5.         </receiver>

And you can check the EXTRA_STATE in the intent given with the broadcast:

Code (Text):

1. String callState = intent.getStringExtra(TelephonyManager.EXTRA_STATE);

 

I wrote an article with detailed instructions, how to make it.

I used broadcast receiver for outgoing calls, and PhoneStateListener for incoming. Calls detection code running in service.

Article include detailed source code. You can modify it for your own needs.

You can see it here:
BitGriff: Detecting incoming and outgoing phone calls on Android.